Dover-Sherborn Middle School assistant headmaster Scott Kellett has been appointed interim headmaster after the unexpected resignation of Frederick Randall, who cited personal reasons in leaving the position on Dec. 10. Superintendent Valerie Spriggs said she is now concentrating on moving forward. “We are very fortunate that Scott Kellett has former experience as a headmaster, we are in good hands,” she said. Spriggs said in the aftermath of the school shootings in Newtown, Conn., her focus has been on getting through the vacation and trying to determine whether there is something her system can do to “help support the people of Newtown. Things have frankly been fast and furious,” she said. “To be really honest, right now we’re just trying to get past that.”